1、Designation: D4440 08D4440 15Standard Test Method forPlastics: Dynamic Mechanical Properties Melt Rheology1This standard is issued under the fixed designation D4440; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method outlines the use of dynamic mechanical instrumentation in determining and reporting the rheologicalproper
3、ties of thermoplastic resins and other types of molten polymers. It may be used as a method for determining the complexviscosity and other significant viscoelastic characteristics of such materials as a function of frequency, strain amplitude,temperature, and time. Such properties may be influenced
4、by fillers and other additives.1.2 It incorporates a laboratory test method for determining the relevant rheological properties of a polymer melt subjected tovarious oscillatory deformations on an instrument of the type commonly referred to as a mechanical or dynamic spectrometer.1.3 This test metho
5、d is intended to provide a means of determining the rheological properties of molten polymers, such asthermoplastics and thermoplastic elastomers over a range of temperatures by nonresonant, forced-vibration techniques. Plots ofmodulus, viscosity, and tan delta as a function of dynamic oscillation (
6、frequency), strain amplitude, temperature, and time areindicative of the viscoelastic properties of a molten polymer.1.4 This test method is valid for a wide range of frequencies, typically from 0.01 to 100 Hz.1.5 This test method is intended for homogenous and heterogeneous molten polymeric systems
7、 and composite formulationscontaining chemical additives, including fillers, reinforcements, stabilizers, plasticizers, flame retardants, impact modifiers,processing aids, and other important chemical additives often incorporated into a polymeric system for specific functionalproperties, and which c
8、ould affect the processability and functional performance. These polymeric material systems have moltenviscosities typically less than 106 Pas (107 poise).1.6 Apparent discrepancies may arise in results obtained under differing experimental conditions. Without changing theobserved data, reporting in
9、 full (as described in this test method) the conditions under which the data was obtained may enableapparent differences observed in another study to be reconciled.1.7 Test data obtained by this test method are relevant and appropriate for use in engineering design.1.8 The values stated in SI units
10、are to be regarded as the standard. The values given in parentheses are for information only.1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health prac
11、tices and determine the applicability of regulatorylimitations prior to use.NOTE 1This test method is equivalent to ISO 6721, Part 10.2. Referenced Documents2.1 ASTM Standards:2D4000 Classification System for Specifying Plastic MaterialsD4065 Practice for Plastics: Dynamic Mechanical Properties: Det
12、ermination and Report of ProceduresD4092 Terminology for Plastics: Dynamic Mechanical PropertiesE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 ISO Standard:3ISO 6721, Part 10 Plastics Determination PlasticsDetermination of Dynamic Mechanical Prop
13、erties, Part 10, ComplexShear Viscosity Using a Parallel-Plate Oscillatory Rheometer1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved Aug. 1, 2008Jan. 15, 2015. Publ
14、ished September 2008February 2015. Originally approved in 1984. Last previous edition approved in 20072008as D4440 - 07.D4440 - 08. DOI: 10.1520/D4440-08.10.1520/D4440-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annu
15、al Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.This document is not an ASTM standard and is intended only to
16、 provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof
17、 the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 DefinitionsDefinitions are
18、 in accordance with Terminology Standard D4092.4. Summary of Test Method4.1 A known amount of thermoplastic polymer (molten powder or pellet, or solid preform disk) is placed in mechanicaloscillation at a fixed or varying frequency at isothermal conditions or over a linear temperature increase or a
19、time-temperaturerelation simulating a processing condition. Storage (elastic) modulus, G or loss (viscous) modulus, G, or both, or thecorresponding dynamic viscosity functions n = gw and n = gw, of the polymeric material specimen are measured in shear asa function of frequency, strain, temperature,
20、or time.5. Significance and Use5.1 This test method provides a simple means of characterizing the important rheological properties and viscosity ofthermoplastic polymers using very small amounts of material (approximately 25 to 50 mm in diameter by 1 to 3 mm in thickness. approximately 3 to 5 g). Da
21、ta may beare generally used for quality control, research and development, and establishment ofoptimum processing conditions.5.2 Dynamic mechanical testing provides a sensitive method for determining molten polymer properties by measuring theelastic and loss moduli as a function of frequency, strain
22、, temperature, or time. Plots of viscosity, storage, and loss moduli, andtan delta as a function of the aforementioned process parameters provide graphical representation indicative of molecular weight,molecular weight distribution, effects of chain branching, and melt-processability for specified c
23、onditions.5.3 Values obtained in this test method can be used to assess the following:5.3.1 Complex viscosity of the polymer melt as a function of dynamic oscillation,5.3.2 Processing viscosity, minimum as well as changes in viscosity as a function of experimental parameters,5.3.3 Effects of process
24、ing treatment,5.3.4 Relative polymer behavioral properties, including viscosity and damping, and5.3.5 Effects of formulation additives that might affect processability or performance.5.4 Before proceeding with this test method, reference should be made refer to the specification offor the material b
25、eing tested.Any test specimen preparation, conditioning, dimensions, or testing parameters, or combination thereof, covered in the relevantASTM materials specification shall take precedence over those mentioned in the test method. If there are no relevant ASTMmaterial specifications, then the defaul
26、t conditions apply.6. Interferences6.1 Since small quantities of polymer are used, it is essential that the specimens be homogeneous and representative.6.2 Toxic or corrosive effluents, or both, may have the potential to be released when heating the polymer specimen to its moltenstate and could be h
27、armful to personnel or to the instrumentation.6.3 Entrapped air/gas may has the potential to affect the results obtained using powder or pellet-type samples.7. Apparatus7.1 The function of the apparatus is to hold a molten polymer of known volume and dimensions so that the material acts as theelasti
28、c and dissipative element in a mechanically driven oscillatory system, as outlined in Practice D4065. These instrumentsoperate in one or more of the following modes for measuring rheological behavior in dynamic oscillatory shear: (1) forced constantamplitude, fixed frequency, (2) forced constant amp
29、litude, varying frequency, and (3) forced varying amplitude, fixed frequency.7.2 The apparatus shall consist of the following:7.2.1 Test FixturesA choice of either polished cone and plate (having a known cone angle) or parallel plates having eithersmooth, polished, or serrated surfaces. Variations o
30、f this tooling, such as bottom plates with concentric overflow rims, can be usedas necessary.7.2.2 Oscillatory Deformation (Strain)A device for applying a continuous oscillatory deformation (strain) to the specimen.7.2.3 DetectorsAdevice or devices for determining dependent and independent experimen
31、tal parameters, such as force (stressor strain), frequency, and temperature. Temperature should be measurable Measure temperature with a precision of 61C,frequency to 61 %, strain to 61 %, and force to 61 %.7.2.4 Temperature Controller and OvenA device for controlling the specimen temperature, eithe
32、r by heating (in steps orramps), cooling (in steps or ramps), or maintaining a constant specimen environment, or a combination thereof. Fig. 1 illustratesseveral time-temperature profiles. A temperature programmer should bethat is sufficiently stable to permit measurement of sampletemperature to 1C.
33、7.3 Nitrogen, or other gas supply for purging purposes, if appropriate.D4440 1528. Test Specimens8.1 The molten polymer composition shouldshall be both homogeneous and representative.8.2 Due to various geometries that might be used for dynamic mechanical characterization of molten polymeric systems,
34、 sizeis not fixed by this test method; however, sample geometry (diameter and thickness) shouldshall be reported for any series ofcomparisons.8.3 Serrated tooling might be usedis an option for materials exhibiting interfacial slippage due to high modulus (as whenapproaching a solidified state).9. Ca
35、libration9.1 Calibrate the instrument using procedures recommended by the manufacturer.10. Procedure10.1 Lower the upper test fixture so that it is just touching the bottom fixture. Zero the gap indicator dial.10.2 If a dynamic temperature sweep (linear heating rate or ramp temperature scan) is requ
36、ired for the specimen, then the gapsetting must be corrected for the thermal expansion of the support fixtures during testing.10.2.1 Determine the thermal expansion of the fixtures at the temperature sweep conditions to be used during testing. Recordthe gap-setting reading at the time and temperatur
37、e corresponding to computer calculation of the viscoelastic properties, whilemaintaining a fixed normal force between the test fixtures.10.2.2 Plot the gap-separation reading, due to thermal expansion of the fixtures, as a function of temperature.10.2.3 Adjust the upper test fixture during the test
38、in order to maintain a fixed sample thickness, if necessary.10.3 Apply an adequate amount of polymer material onto the test fixture. Be certain that there is sufficient material to cover thebottom plate uniformly.10.4 Bring down the upper test fixture so that it is touching the polymeric material.10
39、.4.1 A gap setting from 1 to 3 mm is a good operating range for parallel plate geometry. This gap setting is arbitrary anddependent on the type of material being characterized.Agap setting of 0.5 mm would be a minimum. However, when large platensand low-viscosity materials are being used, the recomm
40、ended minimum gap setting is 0.25 mm.10.4.2 Cone and plate experiments should be conducted at an isothermal temperature. Any change in the temperature settingwill require adjustment of the gap at the new temperature.10.4.2 Remove excess material flush to the test fixtures using a razor blade, spatul
41、a, knife, or hot soldering iron, as appropriate.10.5 Isothermal Evaluations at Elevated Temperature:10.5.1 In cases where the specimen is introduced directly into the test chamber at elevated temperatures, preheat and stabilizethe chamber to the desired temperature prior to introducing the test spec
42、imen.10.5.2 Cone and plate experiments are generally conducted at an isothermal temperature.Any change in the temperature settingsrequire adjustment of the gap at the new temperature.10.6 Isothermal Evaluations at Elevated Temperature: Ramped or Simulated Process Program Heating10.5.1 In cases where
43、 the specimen can be introduced directly into the test chamber at elevated temperatures, preheat andstabilize the chamber to the desired temperature prior to introducing the test specimen. For materials that are to be characterizedFIG. 1 Rheological Properties of a Polymer MeltD4440 153starting at a
44、 low temperature, and controlled for either a linear ramp or step-and-hold function, apply the material to the test toolingand the test chamber closed and heated at the desired rate. It is recommended that temperature be monitored during this heat-up.Thermal gradients of 3 to 5C/min are recommended
45、for measuring the rheological properties. For both isothermal and simulatedprocessing conditions, discontinue measurements when the polymeric composition exhibits deterioration, degradation, ordecomposition since the degradation of the polymer will affect the test results.10.5.2 Ramped or Simulated
46、Process Program HeatingFor materials that are to be characterized starting at a low temperature,and controlled for either a linear ramp or step-and-hold function, the material should be applied to the test tooling and the testchamber closed and heated at the desired rate. Temperature should be monit
47、ored during this heat-up. Thermal gradients of 3 to5C/min are recommended for measuring the rheological properties. For both isothermal and simulated processing conditions,measurements should be discontinued when the polymeric composition exhibits deterioration, degradation, or decomposition sinceth
48、e degradation of the polymer will affect the test results.10.7 Maximum strain amplitude shouldshall be within the linear viscoelastic range of the material. Automated strain sweepsmay be conducted to determine the strain sensitivity of the polymeric material. material are recommended. This is especi
49、allyhelpful for characterizing the effects of fillers and for monitoring crystallization as the molten polymer slowly cools down.NOTE 2There are several devices capable of testing in the non-linear viscoelastic region for obtaining long chain branching information. Higherstrains can be used as long as the device is capable of repeatable measurements and a harmonic analysis is applied to the resulting signal.10.8 Duplicate measurements are recommended.11. Calculation11.1 The following equations listed in Practice D4065 are used to calculate the important
